Photomechanical processing steps include a step for converting a continuous tone original document into a half-tone dot image, that is, a step for converting a continuous tone density variation into a group of half-tone dots each having an area in proportion as the densities are varied.
In the steps, a photographic technique capable of reproducing superhigh contrast images has been used, namely, a technique in which an original picture is photographed through an intersecting line screen or a contact screen and is then treated in an infectious development.
Lithographic type silver halide photographic light-sensitive materials applicable to the infectious development may be unable to provide satisfactory high-contrast images unless they are treated with an infectious developer that is a lith-type developer. For example, in the case that they are developed with an MQ or PQ developer, the resulting gamma value may reach only 5 to 6 at the utmost and there produces many fringes of dots which have to be eliminated at all to form half-tone dots. It has, therefore, been considered that an infectious developer having lower preservability is to be inevitably used in combination.
In this connection, there have been the research and development of the techniques with the aim of forming superhigh contrast images, such as obtained by the infections developer, by the use of a developer having a high sulfite ion concentration and an excellent preservability and capable of performing a rapid treatment. One of the known examples thereof is a technique disclosed in Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) No. 56-106244/1981. In this technique, a specific compound, that is so-called a contrast increasing agent is made present in a silver halide photographic light-sensitive material, hereinafter referred to as light-sensitive material, and specific silver halide grains and other photographic additives are used in combination so as to satisfactorily display the contrast increasing characteristics of the compound.
This type of silver halide photographic light-sensitive materials may be able to provide superhigh contrast photographic images when treating them with a developer having an excellent preservability and capable of performing a rapid treatment. However, the light-sensitive materials produce a sand-like fogged dots so-called black dots in half-tone images in the course of forming a half-tone image, so that the half-tone image quality is deteriorated. To solve this problem, the attempts of solving the problem have been tried by adding a variety of stabilizers and inhibitors each having hetero atoms. However, it has not been said that the problem could be solved thereby.